Flashlight construction



June 9, 1959 YlCK c. CHENG 2,890,327

FLASHLIGHT CONSTRUCTION I 7 Filed July is, 1955 1N VENTOR 7 BY ElmATTORNEYS United States Patent FLASHLIGHT CONSTRUCTION Yick C. Cheng,Kowloon, HOllg Kong, assignor, by mesne assignments, to The ElectricStorage Battery Company, Philadelphia, Pa., a corporation of New JerseyApplication July '19, 1955, Serial No. 523,093

4 Claims. (Cl. 240-106) This invention relates to a novel type ofinsulator for the reflector bowl of a flashlight, whose function is toinsulate the electrically conductive undersurface of the reflector bowlfrom the metallic flashlight casing. A

- particularly desirable feature of the insulator of the presentinvention is the tight seal which may be obtained between the lens ofthe flashlight and the reflector bowl.

Very little attention has been devoted in the past to this structuralcomponent of a flashlight. In a typical lens and reflector assembly fora flashlight, a primary component of the assembly is the lens ringhaving some type of flanged aperture, with the glass or plastic lenspositioned in abutment against the flange. Seated against the flatundersurface of the lens is a reflector bowl having a reflective metalsurface, and an undersurface coating of electrically conductive copper,with an open, centrally disposed, threaded cylinder within which thelamp is secured. Ordinarily, the electrical circuit in the flashlight iscompleted by a contact strip in physical and electrical contact with theundersur-face of the reflector bowl. Usually, both the contact strip andthe metallic flashlight casing are in electrical contact with the bottomterminal of a dry cell in the flashlight. In order to avoid continuousoperation of the light, and allow for the use of a control switch in thecircuit, it is therefore essential that the reflector bowl be carefullyelectrically insulated from the metallic flashlight casing. This isaccomplished frequently by a strip of cardboard or a like insulatingmaterial which is inserted in some fashion between the reflector and theflashlight casing.

In order to maintain the reflector in engagement with the lens and lensring and to prevent accidental dislocation of the respective componentparts of this assembly, there is frequently provided a helical spring ofstrong wire which engages both the reflector bowl and the interiorsurface of the flashlight casing. This spring forces the reflectoragainst the lens. In order to prevent electrical contact between thecasing and the reflector bowl through the metallic wire spring, at leastpart of the spring is usually electrically insulated by a thin plasticsleeve, frequently referred to as spaghetti.

With a lens and reflector assembly of this type, it was found that theearliest point at which deterioration of the flashlight casing wasnoticeable was the exposed metallic surface of the reflector bowl. Thiswas particularly noticeable in warm, humid climates. Another frequentsource of trouble in such a flashlight assembly was in the lens. It wasfound that a glass lens in particular was susceptible to cracking uponsudden impacts, such as would be caused by dropping the flashlightagainst a hard surface. Still another drawback to a construction of thistype is the large amount of labor required for the complex assemblyoperations involved in placing the cardboard insulating piece and theinsulated spring in position.

Accordingly, it is an object of the present invention to provide a noveltype of plastic insulator which will be sturdy, simple to assemble, andwhich will eliminate a large percentage of the labor requirement forassembly of the lens and reflector components.

Another object of the invention is to provide a resilient, 5 plasticinsulator which will also function as a gasket between the reflectorbowl and the lens, whereby an airtight seal may be obtained between thelens and reflector bowl for the elimination of corrosion of the interiorexposed metallic surfaces of the reflector bowl.

Yet another object of the invention is the provision of a resilientgasket between the lens and reflector bowl in the front end cap assemblyof a flashlight, in order to minimize the effect of impact shocks on thefront end cap assembly by providing a cushion between the lens and thereflector bowl.

A still further object of the invention is to provide an insulator for aflashlight reflector bowl which will also function to insulate a pianowire spring used in the assembly from the reflector bowl.

These and other objects of the invention are achieved by the novelplastic insulator of the present invention. This insulator is in theform of a cylindrical ring of U-shaped cross-section, with the innerwall or web of the U being slightly inturned and inclined to thevertical, 5 while the outer web or wall of the U is in the form of awall of a cylinder. Integrally secured to the outer wall of the ring atthe point where it unites with the bight of the U, there is an upwardlyand inwardly directed flange which forms a recessed channel with the 0bight of the U. The peripheral flange conventionally provided on areflector bowl, as a bearing surface against the lens, may be seatedwithin this recessed channel. The portion of the plastic insulator whichis interposed between the peripheral flange of the reflector bowl andthe lens forms a resilient cushion between the lens and the reflectorbowl. This cushion decreases the effect of sharp impacts on the lens,and at the same time, when 'placed under slight compression, forms ahermetic seal between the lens and the reflector bowl. Such a seal isvery advantageous in preventing corrosion of the reflector bowl. Whereit is desired to use a wire spring to urge the reflector bowl intocontact with the lens, the wire spring may be seated within the bight ofthe U- shaped ring which encloses it sufliciently so that there need beno additional insulation placed on the wire spring itself.

These and other features of the invention may be best understood byreference to the drawings, in which:

Fig. 1 is a side elevational view of a flashlight lens and reflectorassembly according to the present invention, in partial section; I

Fig. 2 is a top plan view of the reflector insulator;

Fig. 3 is a plan view of the undersurface of the reflector insulator;

Fig. 4 is a sectional view of the reflector insulator taken on line 44of Fig. 2.

Referring now in detail to the drawings, a flash-light casing 11 isprovided with a conventional type of lens ring 10 having an inturned lip9 against which a lens 14 is positioned in abutting relation. Seatedagainst the lens is a reflector bowl 12, the peripheral flange 21 ofwhich bears against the inner surface of the lens. Seated around thereflector 12 and embracing the peripheral flange 21 thereof with in arecess 18 therein, is the reflector insulator 13. Interposed between theperipheral flange 21 and the opposed surface of the lens 14 is the upperextremity or lip 23 of an inwardly directed flange 19. Extendinginwardly and downwardly, in snug engagement with the underlyingundersurface of the reflector bowl, is an inner web 17. The snugengagement between the web 17 and the underlying undersurface of thereflector bowl enhances the pneumatic seal which is obtainedbetween theperipheral-flange 21 of the reflector bowl and the lens 14, and at thesame time insulates the undersurface of the reflector bowl 12 againstcontact with the flashlight casing 11 and the metallic front end cap 10.Another integral part of the reflector insulator is an abbreviatedcylindrical tube or apron 16, which forms the outer wall of a ring ofsubstantially U-shaped cross-section. The abbreviated cylindrical tube16 adds rigidity to the structure and facilitates the insertion of theperipheral flange 21 of the reflector bowl within the recessed channel18 in the reflector insulator. The cylindrical tube 16 also forms theouter wall of a pocket within which the wire spring may be seated ininsulated relationship with respect to the undersurface of the reflectorbowl 12. The wire spring 15 may be seated against the bight 20 of theU-shaped ring, and at its other extremity may beseated against ashoulder within the flashlight end cap 10.

The slight compression applied by the wire spring 15 suflices to urgethe peripheral flange 21 of the reflector bowl into a mild compressiveengagement with the inner surface of the lens 14., The mild compressiondesirably distorts the lip 23 of the reflector insulator so that itfunctions as a gasket and forms an air-tight seal between the glass lens14 and the interior of the reflector bowl 112. In order to obtain thisgasket effect, it is necessary that the reflector insulator beconstructed of a resilient material. Two highly satisfactory plasticsfor the construction of the reflector insulator, of the several whichmay be employed, are the polyvinyl plastics and the polyethyleneplastics. The particular plastic employed may be selected on the basisof its strength characteristics, appearance, ease of handling,age-resistance and insulating properties. Of these plastics, apolyethylene plastic having a molecular weight in the range of 10,000 to20,000 is preferred.

While it is preferred that the reflector insulator disclosed be employedin combination with a wire spring of the type illustrated in Fig. 1, sothat a mild compressive action is obtained, and so that accidentaldislocation of the lens and reflector assembly during this assembly orreassembly of the entire flashlight is prevented, it should beunderstood that the presence of the wire spring 15 is not essential inthe assembly. The wire spring 15 may be omitted in many cases, andsuflicient compressive relation to obtain the gasket eifect from thereflector insulator may be obtained through the action of a conventionalbottom spring in the flashlight casing. Other minor modifications in thebasic structure disclosed, which are within the scope of the invention,will occur to those skilled in the art.

I claim:

1. In an improved flashlight structure, a lens ring and a lens, aperipherally flanged reflector bowl in juxtaposition with said lens, aresilient plastic gasket interposed between the lens and peripheralreflector bo'wl flange toobtain a tight seal, said gasket embracing theflange in seating engagement within a channel therein, said gaskethaving a dependent integral Web snugly embracing the undersurface ofsaid bowl to insulate it from the flashlight casing, said gasket alsohaving a second dependent integral web in abbreviated cylindrical form,said webs being integrally interconnected in a structure of invertedU-shaped cross-section, and a wire spring seated against the bight ofsaid U and engaging the walls of the flashlight casing, said springbiasing the reflector bowl toward engagement with the lens and therebycompressing the resilient gasket.

2. In an improved flashlight structure, a lens ring and lens, aperipherally flanged reflector bowl spring-biased into juxtapositionwith said lens, and a resilient plastic gasket element part of which isinterposed under com.- pression between the lens and reflector bowlflange, whereby a tight seal is obtained, said gasket element having achannel within which the reflector bowl flange is seated; a dependentweb snugly embracing the undersurface of said bowl and insulating itfrom the flashlight casing while providing a seal between the lens andthe interior of the reflector bowl; a second dependent web ofabbreviated cylindrical form attached at one end about said gasketelement, said second dependent web imparting rigidity to said gasketelement, said dependent webs forming between them an inverted recessedseat for a biasing spring.

3. In a flashlight having a cap, a lens and a reflector bowl below saidlens, said bowl having a peripheral flange at the top thereof, theimprovement which cornprises; an integral resilient sealing andinsulating clement, said element having an interior annular channelembracing the said flange of said bowl thereby providing a lip portioninterposed between said lens and said flange, said element having adownwardly depending, inwardly in clined annular web below said channel,said web being shaped to conform to and embrace the other portion ofsaid bowl below the flange thereof, said element having a secondintegral, downwardly depending annular web outwardly spaced from saiddownwardly inclined web, thereby providing a recessed inverted scatbetween said webs.

4. The improvement claimed in claim 3 in which a wire spring is confinedunder compression between the said flashlight cap and the said recessedinverted seat, said spring biasing the reflector bowl toward the lensand thereby compressing the said interposed lip portion of saidresilient sealing and insulating element.

References Cited in the file of this patent UNITED STATES PATENTS1,299,909 Burgess Apr. 8, 1919 1,560,278 Mahan Nov. 3, 1925 1,595,146Ford Aug. 10, 1.926 2,264,284 Bassett Dec. 2, 194] 2,304,742 OfficerDec. 8, 1942 2,602,114 Fisch July 1, 1952 2,613,314 Garland Oct. 7, 1952FOREIGN PATENTS 489,382 Great Britain July 26, 1938

